Electron–ion Recombination Rate Coefficients for C Ii Forming C I

Abstract

We have determined absolute dielectronic recombination rate coefficients for C ii, using the CRYRING heavy-ions storage ring. The resonances due to 2s-2p ( n = 0) core excitations are detected in the center-of-mass energy range of 0-15 eV. The experimental results are compared with intermediate coupling AUTOSTRUCTURE calculations. Plasma rate coefficients are obtained from the DR spectrum by convoluting it with a Maxwell-Boltzmann energy distribution for temperatures in the range of 10 3 -10 6 K. The derived temperature-dependent plasma recombination rate coefficients are presented graphically and parameterized by using a fit formula for convenient use in plasma modeling codes. The experimental rate coefficients are also compared with the theoretical data available in literature. In the temperature range of 10 3 -2 × 10 4 K, our experimental results show that previous calculations severely underestimate the plasma rate coefficients and also our AUTOSTRUCTURE calculation does not reproduce the experimental plasma rate coefficients well. Above 2×10 4 K, the agreement between the experimental and theoretical rate coefficients is much better, and the deviations are smaller than the estimated uncertainties.

KLL Dielectronic Recombination of Highly Charged Sulfur and Silicon Ions

“…The Auger decay rates and resonant strengths were calculated by using a code developed by Y. M. Li et al [15]. These codes were already used successfully for the calculations of DR resonance strengths and energy position of different atomic ions [6,16,17]. The generalized Breit interactions (GBI) and the decay through forbidden radiation are very weak; therefore such effects were not taken into account.…”

“…For example, DR satellite lines from fusion plasma devices are often used to determine plasma temperature for diagnostics [2]. On the other hand, plasma modelling codes such as XSTAR [3], CLOUDY [4], and CHIANTI [5] crucially depend upon the input atomic data such as DR cross sections and rate coefficients to obtain ionization balance and physical conditions of the plasmas [6]. Highly charged sulfur and silicon ions are present in astrophysics and laboratory plasmas [7,8].…”

Physics book: CRYRING@ESR

“…A closer inspection suggests that C + might be a good candidate for a proof-of-principle experiment. C + ions were already stored in CRYRING, when it was still located in Stockholm, and used for electron-ion recombination experiments (Ali et al, 2012 1.…”

Absolute rate coefficients for photorecombination of beryllium-like and boron-like silicon ions

“…The boron isoelectronic sequence has been less intensely studied. DR rate coefficients from storage-ring experiments are available for C + [30], Ne 3+ [31], Mg 7+ [32], Ar 13+ [33,34], and Fe 21+ [35,36]. State-of-the-art theoretical DR (and TR) calculations have been carried out by Colgan et al [37] and by Altun et al [38,39], respectively, for Be-like and B-like ions of astrophysical interest with the nuclear charge ranging up to Z = 54.…”